1. Technical Field
The present invention relates in general to an improved drive system in a fluid screening operation and, in particular, to an improved system, method, and apparatus for hydraulically or pneumatically driving a fluid screening system as well as sensing and correcting an overload in the fluid screening system.
2. Background of the Invention
Bar screens are used for screening solids and debris from flowing liquid streams. An example of such a bar screen system can be found in U.S. Pat. No. 5,730,862. In such systems, a series of rakes pass over parallel screen bars, which make up a bar screen field and remove the debris collected from the flowing stream. Occasionally, large pieces of debris can clog and even damage the bar screen field by either bending or breaking one or more bars within the bar screen field. Furthermore, such blockage can cause the fluid to overflow the filter system. When damage does occur, the screen system must be repaired by typically cutting out the affected bars and welding new bars in their place. These repairs are time consuming, potentially hazardous, and expensive. The screen system is typically taken out of service for a relatively long period of time in order to make such repairs, which also adds significantly to the costs of the repairs.
Some prior art systems have tried to address this problem by using nozzles to spray the debris off of the rakes and screen, or either reversing the direction of travel for the rakes until the impediment has been removed from the screen. However, these attempts are not always successful at clearing the screen enough to continue operation of the system, especially when the debris is relatively large size. Thus, a need exists for an improved screen system, and preferably one that can prevent or avoid such extensive damage and repairs. Ideally, such a system should be capable of being adapted to the specific fluid applications and also be able to be used on existing screen system equipment with minimal modification.